Subject: Re: FFSv1 performance on large filesystems
To: Matthias Scheler <tron@zhadum.de>
From: Thor Lancelot Simon <tls@rek.tjls.com>
List: tech-kern
Date: 03/03/2005 10:32:42
On Thu, Mar 03, 2005 at 01:05:51PM +0000, Matthias Scheler wrote:
> 	Hello,
> 
> while searching for the reason for the "bad" NFS performance in my home
> network I got interesting filesystem performance numbers
> 
> Filesystem Size		Device	Write Performance(*)
> 1.9G			raid0	34MB/Sec
> 101G			raid0	22MB/Sec <--

How large is the underlying disk?  You should see a significant difference
in performance from center to edge of the disk.

How large is the file you're writing?  If you want contiguous writes of
very very large files you'll need to play with the -e option to newfs.

I actually think that, in any case where we have more than 100 or so
cylinder groups, we should default -e to be a full group (it would be
nice if it could meaningfully be _more_ than a group).

Thor